As I learned more about the Dvorak layout, I stumbled on an IBM research project for improving PDA input called "SHARK" (using a specially designed keyboard called "ATOMIK"). More information can be found on the following link:

I think this is a really neat idea, although I can see a couple of issues (patent and closed-source copyright) that could keep this from getting to the Zaurus. Of course, since IBM has embraced Linux, they might even consider open-sourcing this project! especially since the web-page seems to be about two years old.